Support Consul Connect Envoy Command on Windows (#17694)

### Description

Add support for consul connect envoy command on windows. This PR fixes
the comments of PR - https://github.com/hashicorp/consul/pull/15114

### Testing
* Built consul.exe from this branch on windows and hosted here - [AWS
S3](https://asheshvidyut-bucket.s3.ap-southeast-2.amazonaws.com/consul.zip)
* Updated the
[tutorial](https://developer.hashicorp.com/consul/tutorials/developer-mesh/consul-windows-workloads)
and changed the `consul_url.default` value to [AWS
S3](https://asheshvidyut-bucket.s3.ap-southeast-2.amazonaws.com/consul.zip)
* Followed the steps in the tutorial and verified that everything is
working as described.

### PR Checklist

* [x] updated test coverage
* [ ] external facing docs updated
* [x] appropriate backport labels added
* [x] not a security concern

---------

Co-authored-by: Franco Bruno Lavayen <cocolavayen@gmail.com>
Co-authored-by: Jose Ignacio Lorenzo <74208929+joselo85@users.noreply.github.com>
Co-authored-by: Jose Ignacio Lorenzo <joseignaciolorenzo85@gmail.com>
Co-authored-by: Dhia Ayachi <dhia@hashicorp.com>

.changelog/17694.txt

@@ -0,0 +1,3 @@
+```release-note:feature
+Windows: support consul connect envoy command on Windows
+```

command/connect/envoy/envoy.go

@@ -38,7 +38,7 @@ func New(ui cli.Ui) *cmd {
 	return c
 }
 
-const DefaultAdminAccessLogPath = "/dev/null"
+const DefaultAdminAccessLogPath = os.DevNull
 
 type cmd struct {
 	UI     cli.Ui

command/connect/envoy/exec_supported.go

@@ -0,0 +1,55 @@
+//go:build linux || darwin || windows
+// +build linux darwin windows
+
+package envoy
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+func isHotRestartOption(s string) bool {
+	restartOpts := []string{
+		"--restart-epoch",
+		"--hot-restart-version",
+		"--drain-time-s",
+		"--parent-shutdown-time-s",
+	}
+	for _, opt := range restartOpts {
+		if s == opt {
+			return true
+		}
+		if strings.HasPrefix(s, opt+"=") {
+			return true
+		}
+	}
+	return false
+}
+
+func hasHotRestartOption(argSets ...[]string) bool {
+	for _, args := range argSets {
+		for _, opt := range args {
+			if isHotRestartOption(opt) {
+				return true
+			}
+		}
+	}
+	return false
+}
+
+// execArgs returns the command and args used to execute a binary. By default it
+// will return a command of os.Executable with the args unmodified. This is a shim
+// for testing, and can be overridden to execute using 'go run' instead.
+var execArgs = func(args ...string) (string, []string, error) {
+	execPath, err := os.Executable()
+	if err != nil {
+		return "", nil, err
+	}
+
+	if strings.HasSuffix(execPath, "/envoy.test") {
+		return "", nil, fmt.Errorf("set execArgs to use 'go run' instead of doing a self-exec")
+	}
+
+	return execPath, args, nil
+}

command/connect/envoy/exec_unix.go

@@ -12,63 +12,12 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"strings"
 	"syscall"
 	"time"
 
 	"golang.org/x/sys/unix"
 )
 
-// testSelfExecOverride is a way for the tests to no fork-bomb themselves by
-// self-executing the whole test suite for each case recursively. It's gross but
-// the least gross option I could think of.
-var testSelfExecOverride string
-
-func isHotRestartOption(s string) bool {
-	restartOpts := []string{
-		"--restart-epoch",
-		"--hot-restart-version",
-		"--drain-time-s",
-		"--parent-shutdown-time-s",
-	}
-	for _, opt := range restartOpts {
-		if s == opt {
-			return true
-		}
-		if strings.HasPrefix(s, opt+"=") {
-			return true
-		}
-	}
-	return false
-}
-
-func hasHotRestartOption(argSets ...[]string) bool {
-	for _, args := range argSets {
-		for _, opt := range args {
-			if isHotRestartOption(opt) {
-				return true
-			}
-		}
-	}
-	return false
-}
-
-// execArgs returns the command and args used to execute a binary. By default it
-// will return a command of os.Executable with the args unmodified. This is a shim
-// for testing, and can be overridden to execute using 'go run' instead.
-var execArgs = func(args ...string) (string, []string, error) {
-	execPath, err := os.Executable()
-	if err != nil {
-		return "", nil, err
-	}
-
-	if strings.HasSuffix(execPath, "/envoy.test") {
-		return "", nil, fmt.Errorf("set execArgs to use 'go run' instead of doing a self-exec")
-	}
-
-	return execPath, args, nil
-}
-
 func makeBootstrapPipe(bootstrapJSON []byte) (string, error) {
 	pipeFile := filepath.Join(os.TempDir(),
 		fmt.Sprintf("envoy-%x-bootstrap.json", time.Now().UnixNano()+int64(os.Getpid())))

command/connect/envoy/exec_unsupported.go

@@ -1,8 +1,8 @@
 // Copyright (c) HashiCorp, Inc.
 // SPDX-License-Identifier: MPL-2.0
 
-//go:build !linux && !darwin
-// +build !linux,!darwin
+//go:build !linux && !darwin && !windows
+// +build !linux,!darwin,!windows
 
 package envoy
 

command/connect/envoy/exec_windows.go

@@ -0,0 +1,110 @@
+//go:build windows
+// +build windows
+
+package envoy
+
+import (
+	"errors"
+	"fmt"
+	"github.com/natefinch/npipe"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"time"
+)
+
+func makeBootstrapPipe(bootstrapJSON []byte) (string, error) {
+	pipeFile := filepath.Join(os.TempDir(),
+		fmt.Sprintf("envoy-%x-bootstrap.json", time.Now().UnixNano()+int64(os.Getpid())))
+
+	binary, args, err := execArgs("connect", "envoy", "pipe-bootstrap", pipeFile)
+	if err != nil {
+		return pipeFile, err
+	}
+
+	// Dial the named pipe
+	pipeConn, err := npipe.Dial(pipeFile)
+	if err != nil {
+		return pipeFile, err
+	}
+	defer pipeConn.Close()
+
+	// Start the command to connect to the named pipe
+	cmd := exec.Command(binary, args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	cmd.Stdin = pipeConn
+
+	// Start the command
+	err = cmd.Start()
+	if err != nil {
+		return pipeFile, err
+	}
+
+	// Write the config
+	n, err := pipeConn.Write(bootstrapJSON)
+	if err != nil {
+		return pipeFile, err
+	}
+
+	if n < len(bootstrapJSON) {
+		return pipeFile, fmt.Errorf("failed writing boostrap to child STDIN: %s", err)
+	}
+
+	// We can't wait for the process since we need to exec into Envoy before it
+	// will be able to complete so it will be remain as a zombie until Envoy is
+	// killed then will be reaped by the init process (pid 0). This is all a bit
+	// gross but the cleanest workaround I can think of for Envoy 1.10 not
+	// supporting /dev/fd/<fd> config paths any more. So we are done and leaving
+	// the child to run it's course without reaping it.
+	return pipeFile, nil
+}
+
+func startProc(binary string, args []string) (p *os.Process, err error) {
+	if binary, err = exec.LookPath(binary); err == nil {
+		var procAttr os.ProcAttr
+		procAttr.Files = []*os.File{os.Stdin,
+			os.Stdout, os.Stderr}
+		p, err := os.StartProcess(binary, args, &procAttr)
+		if err == nil {
+			return p, nil
+		}
+	}
+	return nil, err
+}
+
+func execEnvoy(binary string, prefixArgs, suffixArgs []string, bootstrapJSON []byte) error {
+	tempFile, err := makeBootstrapPipe(bootstrapJSON)
+	if err != nil {
+		os.RemoveAll(tempFile)
+		return err
+	}
+	// We don't defer a cleanup since we are about to Exec into Envoy which means
+	// defer will never fire. The child process cleans up for us in the happy
+	// path.
+
+	// We default to disabling hot restart because it makes it easier to run
+	// multiple envoys locally for testing without them trying to share memory and
+	// unix sockets and complain about being different IDs. But if user is
+	// actually configuring hot-restart explicitly with the --restart-epoch option
+	// then don't disable it!
+	disableHotRestart := !hasHotRestartOption(prefixArgs, suffixArgs)
+
+	// First argument needs to be the executable name.
+	envoyArgs := []string{}
+	envoyArgs = append(envoyArgs, prefixArgs...)
+	if disableHotRestart {
+		envoyArgs = append(envoyArgs, "--disable-hot-restart")
+	}
+	envoyArgs = append(envoyArgs, suffixArgs...)
+	envoyArgs = append(envoyArgs, "--config-path", tempFile)
+
+	// Exec
+	if proc, err := startProc(binary, envoyArgs); err == nil {
+		proc.Wait()
+	} else if err != nil {
+		return errors.New("Failed to exec envoy: " + err.Error())
+	}
+
+	return nil
+}

go.mod

@@ -86,6 +86,7 @@ require (
 	github.com/mitchellh/mapstructure v1.5.0
 	github.com/mitchellh/pointerstructure v1.2.1
 	github.com/mitchellh/reflectwalk v1.0.2
+	github.com/natefinch/npipe v0.0.0-20160621034901-c1b8fa8bdcce
 	github.com/oklog/ulid/v2 v2.1.0
 	github.com/olekukonko/tablewriter v0.0.4
 	github.com/patrickmn/go-cache v2.1.0+incompatible
@@ -250,6 +251,7 @@ require (
 	google.golang.org/appengine v1.6.7 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/ini.v1 v1.66.2 // indirect
+	gopkg.in/natefinch/npipe.v2 v2.0.0-20160621034901-c1b8fa8bdcce // indirect
 	gopkg.in/resty.v1 v1.12.0 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect

go.sum

@@ -739,6 +739,8 @@ github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 h1:C3w9PqII01/Oq
 github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822/go.mod h1:+n7T8mK8HuQTcFwEeznm/DIxMOiR9yIdICNftLE1DvQ=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/mxk/go-flowrate v0.0.0-20140419014527-cca7078d478f/go.mod h1:ZdcZmHo+o7JKHSa8/e818NopupXU1YMK5fe1lsApnBw=
+github.com/natefinch/npipe v0.0.0-20160621034901-c1b8fa8bdcce h1:TqjP/BTDrwN7zP9xyXVuLsMBXYMt6LLYi55PlrIcq8U=
+github.com/natefinch/npipe v0.0.0-20160621034901-c1b8fa8bdcce/go.mod h1:ifHPsLndGGzvgzcaXUvzmt6LxKT4pJ+uzEhtnMt+f7A=
 github.com/nicolai86/scaleway-sdk v1.10.2-0.20180628010248-798f60e20bb2 h1:BQ1HW7hr4IVovMwWg0E0PYcyW8CzqDcVmaew9cujU4s=
 github.com/nicolai86/scaleway-sdk v1.10.2-0.20180628010248-798f60e20bb2/go.mod h1:TLb2Sg7HQcgGdloNxkrmtgDNR9uVYF3lfdFIN4Ro6Sk=
 github.com/niemeyer/pretty v0.0.0-20200227124842-a10e7caefd8e/go.mod h1:zD1mROLANZcx1PVRCS0qkT7pwLkGfwJo4zjcN/Tysno=
@@ -1458,6 +1460,8 @@ gopkg.in/inf.v0 v0.9.1 h1:73M5CoZyi3ZLMOyDlQh031Cx6N9NDJ2Vvfl76EDAgDc=
 gopkg.in/inf.v0 v0.9.1/go.mod h1:cWUDdTG/fYaXco+Dcufb5Vnc6Gp2YChqWtbxRZE0mXw=
 gopkg.in/ini.v1 v1.66.2 h1:XfR1dOYubytKy4Shzc2LHrrGhU0lDCfDGG1yLPmpgsI=
 gopkg.in/ini.v1 v1.66.2/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
+gopkg.in/natefinch/npipe.v2 v2.0.0-20160621034901-c1b8fa8bdcce h1:+JknDZhAj8YMt7GC73Ei8pv4MzjDUNPHgQWJdtMAaDU=
+gopkg.in/natefinch/npipe.v2 v2.0.0-20160621034901-c1b8fa8bdcce/go.mod h1:5AcXVHNjg+BDxry382+8OKon8SEWiKktQR07RKPsv1c=
 gopkg.in/resty.v1 v1.9.1/go.mod h1:vo52Hzryw9PnPHcJfPsBiFW62XhNx5OczbV9y+IMpgc=
 gopkg.in/resty.v1 v1.12.0 h1:CuXP0Pjfw9rOuY6EP+UvtNvt5DSqHpIxILZKT/quCZI=
 gopkg.in/resty.v1 v1.12.0/go.mod h1:mDo4pnntr5jdWRML875a/NmxYqAlA73dVijT2AXvQQo=